Radiation imaging device, image processing method, and image processing program

Abstract

A radiographic imaging apparatus acquires a plurality of two-dimensional pickup images taken at different angles and a three-dimensional image of a processing target imaged in advance. Two-dimensional calculated projection images are generated from the three-dimensional image, respectively, in association with the two-dimensional pickup images. A characteristic region indicates a treatment instrument represented in the two-dimensional pickup image. The two-dimensional pickup image is aligned with the calculated projection image. A deformation amount of the processing target in the two-dimensional pickup image is calculated by comparing the two-dimensional pickup image with the calculated projection image, and a position of the characteristic region is corrected. A three-dimensional position of the characteristic region is calculated and corrected on the basis of anatomical structure information of the processing target. A position mapping part then superimposes the corrected three-dimensional position of the characteristic region on the three-dimensional image to be displayed on a display unit.

What is claimed is: 
     
       1. A radiographic imaging apparatus comprising,
 an imager configured to take a plurality of two-dimensional pickup images at different imaging angles, by moving positions of a radiation source and a detector, 
 an image capturing part configured to acquire a three-dimensional image of a processing target imaged in advance, 
 a calculated projection image generator configured to generate two-dimensional calculated projection images from the three-dimensional image, respectively in association with the two-dimensional pickup images, on the basis of the three-dimensional image and the positions of the radiation source and the detector used for taking each of the two-dimensional pickup images, 
 a characteristic region extractor configured to extract a characteristic region indicating a treatment instrument represented in each of the two-dimensional pickup images, 
 an image alignment part configured to align each of the two-dimensional pickup images, with each of the calculated projection images respectively associated with the two-dimensional pickup images, 
 a deformation amount calculation and correction part configured to calculate a deformation amount of the processing target in each of the two-dimensional pickup images, by comparing each of the two-dimensional pickup images with each of the calculated projection images respectively associated with the two-dimensional pickup images, and to correct a position of the characteristic region based on the deformation amount, 
 a three-dimensional position calculator configured to calculate a three-dimensional position of the characteristic region, from the position of the characteristic region corrected in each of the two-dimensional pickup images, and the positions of the radiation source and the detector used for taking each of the two-dimensional pickup images, 
 an anatomical structure position correction part configured to correct the three-dimensional position of the characteristic region based on anatomical structure information of the processing target acquired from the three-dimensional image, and 
 a position mapping part configured to superimpose the three-dimensional position of the characteristic region corrected by the anatomical structure correction part, on the three-dimensional image, and to display the three-dimensional image on which the corrected three-dimensional position of the characteristic region is superimposed. 
 
     
     
       2. The radiographic imaging apparatus according to  claim 1 , wherein,
 the position mapping part superimposes on the three-dimensional image, the three-dimensional position of the characteristic region calculated by the three-dimensional position calculator, together with the corrected three-dimensional position of the characteristic region. 
 
     
     
       3. The radiographic imaging apparatus according to  claim 1 , wherein,
 the deformation amount calculation and correction part comprises, 
 a non-rigid deformation part configured to apply non-rigid deformation to the two-dimensional pickup image, 
 an image comparator configured to compare the two-dimensional pickup image after the non-rigid deformation is applied, with the calculated projection image to calculate a degree is similarity, 
 a deformation parameter calculator configured to calculate a parameter that maximizes the degree of similarity as a non-rigid deformation parameter, and an in-imaging plane position correction part configured to calculate a deformation amount of the characteristic region in the two-dimensional pickup image on the basis of the deformation parameter, to correct the position of the characteristic region. 
 
     
     
       4. The radiographic imaging apparatus according to  claim 2 , wherein,
 the deformation amount calculation and correction part comprises, 
 a non-rigid deformation part configured to apply non-rigid deformation to the two-dimensional pickup image,
 an image comparator configured to compare the two-dimensional pickup image after the non-rigid deformation is applied, with the calculated projection image to calculate a degree is similarity, 
 
 a deformation parameter calculator configured to calculate a parameter that maximizes the degree of similarity as a non-rigid deformation parameter, and 
 an in-imaging plane position correction part configured to calculate a deformation amount of the characteristic region in the two-dimensional pickup image on the basis of the deformation parameter, to correct the position of the characteristic region. 
 
     
     
       5. The radiographic imaging apparatus according to  claim 3 , wherein,
 the deformation amount calculation and correction part further comprises, 
 a pseudo structure adder configured to superimpose a pseudo structure on the three-dimensional image, the pseudo structure representing a shape on the basis of an internal structure of the processing target. 
 
     
     
       6. The radiographic imaging apparatus according to  claim 4 , wherein,
 the deformation amount calculation and correction part further comprises, 
 a pseudo structure adder configured to superimpose a pseudo structure on the three-dimensional image, the pseudo structure representing a shape on the basis of an internal structure of the processing target. 
 
     
     
       7. An image processing method comprising,
 an image capturing step for acquiring a plurality of two-dimensional pickup images of a processing target, taken at different imaging angles by changing positions of a radiation source and a detector, and a three-dimensional image of the processing target imaged in advance, 
 a calculated projection image generating step for generating two-dimensional calculated projection images from the three-dimensional image, respectively in association with the two-dimensional pickup images, on the basis of the three-dimensional image and the positions of the radiation source and the detector used for taking each of the two-dimensional pickup images, 
 a characteristic region extracting step for extracting a characteristic region indicating a treatment instrument represented in each of the two-dimensional pickup images, 
 an image aligning step for aligning each of the two-dimensional pickup images, with each of the calculated projection images respectively associated with the two-dimensional pickup images, 
 a deformation amount calculating and correcting step for calculating a deformation amount of the processing target in the two-dimensional pickup image, by comparing each of the two-dimensional pickup images with each of the calculated projection images respectively associated with the two-dimensional pickup images, and for correcting a position of the characteristic region based on the deformation amount, 
 a three-dimensional position calculating step for calculating a three-dimensional position of the characteristic region, from the position of the characteristic region corrected in each of the two-dimensional pickup images and the positions of the radiation source and the detector used for taking each of the two-dimensional pickup images, 
 an anatomical structure position correcting step for correcting the three-dimensional position of the characteristic region based on anatomical structure information of the processing target acquired from the three-dimensional image, and 
 a position mapping step for superimposing the three-dimensional position of the characteristic region corrected by the anatomical structure correcting step, on the three-dimensional image, and for displaying the three-dimensional image on which thus corrected three-dimensional position of the characteristic region is superimposed. 
 
     
     
       8. A non-transitory computer readable medium storing thereon an image processing program causing a computer to execute,
 an image capturing step for acquiring a plurality of two-dimensional pickup images of a processing target, taken at different imaging angles by changing positions of a radiation source and a detector, and a three-dimensional image of the processing target imaged in advance, 
 a calculated projection image generating step for generating two-dimensional calculated projection images from the three-dimensional image, respectively in association with the two-dimensional pickup images, on the basis of the three-dimensional image and the positions of the radiation source and the detector used for taking each of the two-dimensional pickup images, 
 a characteristic region extracting step for extracting a characteristic region indicating a treatment instrument represented in each of the two-dimensional pickup images, 
 an image aligning step for aligning each of the two-dimensional pickup images, with each of the calculated projection images respectively associated with the two-dimensional pickup images, 
 a deformation amount calculating and correcting step for calculating a deformation amount of the processing target in the two-dimensional pickup image, by comparing each of the two-dimensional pickup images with each of the calculated projection images respectively associated with the two-dimensional pickup images, and for correcting a position of the characteristic region based on the deformation amount, 
 a three-dimensional position calculating step for calculating a three-dimensional position of the characteristic region, from the position of the characteristic region corrected in each of the two-dimensional pickup images and the positions of the radiation source and the detector used for taking each of the two-dimensional pickup images, 
 an anatomical structure position correcting step for correcting the three-dimensional position of the characteristic region based on anatomical structure information of the processing target acquired from the three-dimensional image, and 
 a position mapping step for superimposing the three-dimensional position of the characteristic region corrected by the anatomical structure correcting step, on the three-dimensional image, and for displaying the three-dimensional image on which thus corrected three-dimensional position of the characteristic region is superimposed.